Approximately 1800 kindergarten and first grade children will be randomly assigned to one of the following groups: Group 1 - Will rinse once every week in school with a 0.2% sodium fluoride solution. Group 2 - Will ingest once a day in school a sodium fluoride tablet containing 1 mg. of fluoride. Group III - Will carry out the regimens for both Group I and Group II. The method of assignment should result in three comparable groups each containing 600 children. Participants will carry out their assigned treatments in classrooms under the close supervision of a teacher. Treatments will be administered for a minimum of eight and nine years for first grade and kindergarten, respectively. Baseline dental examinations will be conducted in September 1981. The prescribed treatments will be initiated as soon as the examinations are completed.